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Vital Statistics

Watershed Area 677 acres
Lake surface area 5 acres
Maximum depth 22 feet
Mean depth 9 feet
Public Park Y
Boat Ramp car top
Fish Present carp


Hicklin Lake (also known as Hicks or Garrett) was monitored by volunteers in 1996 through 1998. The data indicated that the lake was highly productive (eutrophic), with fair to poor water quality. Recurring bluegreen blooms have frequently limited beneficial uses of the lake, situated in Lakewood Park. Hicklin Lake was placed on the EPA 303d list of impaired water bodies for both phosphorus and fecal coliform concentrations, although it was reclassified to category 2 in 2008 for fecal coliform bacteria.

A baseline water quality study was completed in 2004, and alum treatments have been carried out to reduce phosphorus in 2005 and again in 2011 by the King County Lake Stewardship Program. Both treatments were successful, with summer monitoring following the condition of the lake to measure effectiveness. Further treatments may be necessary in the future, although improvements in the stormwater facilities and best management practices are ongoing in the watershed.

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This bathymetric map shows contour lines of equal depth, similar to a topographic map would for mountains and valleys. The red 'X' marks the location where water quality samples are taken.
This map shows the area of the watershed relative to the area of the lake. Generally speaking, the larger a watershed is relative to a lake, the greater the influence land use practices on lake water quality.

Click image to enlarge

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Water Quality Data  

Through a combination of efforts by volunteer lake monitors and King County staff, data relating to physical, chemical, and biological aspects of the lake have been collected for most lakes. The King County Lake Stewardship Program analyzes data to track long-term water quality trends in small lakes in western King County.

View or Download Data
Use this tool to view or download data from the lake in tabular format. You can define date ranges and select which parameters to view or download.

Chart Data
Use the charting tool to look at graphs showing single parameters for a single water year at a time.

Water quality over time
A common method of tracking water quality trends in lakes is by calculating the “trophic state index” (TSI) (Carlson, 1977) and testing the values for positive or negative trends over time. TSI indicators predict the biological productivity of the lake based on water clarity (Secchi) and concentrations of total phosphorus (TP) and chlorophyll a (Chlor). Generally at least 8 years of data without major lake management activities are needed to have confidence in a significant trend.

The average of these three TSI indicators during the growing season can be used to place lakes in one of three broad categories:
<40 = oligotrophic (low productivity),
40 to 50 = mesotrophic (moderate productivity)
>50 = eutrophic (highly productive).

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Reports and Related Links

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For questions about lakes in King County, please contact or call the Water and Land Resources Division front desk at 206-477-4800.